Mactaquac Aquatic Ecosystem Study By 2017, NB Power will make a multi-billion dollar decision to rebuild or remove the Mactaquac Dam (MD) on the Saint John River (SJR), near Fredericton, NB, Canada. The Canadian Rivers Institute has been charged with providing the environmental science to support NB Power’s decision. The Mactaquac Aquatic Ecosystem Study (MAES) is a planned, whole-river ecosystem study and manipulation. It begins with a minimum of eight years to study the structure and function of a large river ecosystem, followed by a manipulation of flow, sediment load, and thermal regime with consequential effects on the ecosystem, and then a multi-year period to monitor the recovery to a new river state. The manipulation will induce either an acute, major perturbation with long-term effects, i.e., Mactaquac Dam, Saint John removing the dam and restoring the river to a free-flowing form, or a minor, River (Hatch Consulting) lesser stress event created by the multi-year, re-construction of the dam, but chronic in that the dam and related issues persist. A comprehensive study and planned manipulation of an ecosystem of this scale is arguably the largest freshwater ecosystem study and experiment that has been attempted. We are seeking motivated, self-driven and talented post-doctoral candidates and graduate students in Biology, Civil Engineering, Geological Engineering, Hydrological and Hydrodynamic Modelling, and Fluvial Geomorphology. Beginning Summer 2014 1. MScEng (Geology) - Accurate definition of sediment layering of a reservoir. One of the primary concerns with dam remediation is estimating the volume of sediment accreted since emplacement (45 years in the case of Mactaquac Dam). While the total volume may be large, spread over a large area the local thickness of the sediments may be very thin (decimetres). Digital subbottom profiling records acquired using broadband acoustic sources (28 kHz and 3.5 kHz) will be analyzed to define this layer as well as gravity cores to understand impedance contrasts and advance our interpretation of sediment layers. The 3.5 kHz profiles are also expected to provide insights into the deeper stratigraphy (glacial and post-glacial) that will be controlling the groundwater flux during reservoir drawdown and potentially influencing engineering solutions for the future MD removal or renewal. We will complement the acoustic survey with a towed low power seismic system to obtain greater depths of penetration and/or improved resolution in areas of particular interest. Possible options include the IKB Seistec system previously proven for subbottom aquifer imaging at Fredericton or a sparker-based system capable of greater penetration in coarse sediments and tills. [Supervisor Dr. Karl Butler, UNB Fredericton] 2. MSc (Hydrological Modeling) - Climate and future hydrological regimes for the Saint John River. Working with the modeling team (hydrological/hydraulic/thermal models and paired with downscaled climate information), the MSc Candidate will model trends for the hydrological and thermal regimes predicted for the SJR for different climate scenarios. Different approaches to downscaling climate data will be explored, for example, Statistical Downscaling Model, using modelled climate data available through the Canadian Climate Change Scenarios Network (www.cccsn.ec.gc.ca). This work will set the hydrological foundation for developing appropriate environment flow regimes for the SJR. [Supervisors Dr. Wendy Monk, UNB Fredericton and Dr. Andre St-Hilaire, INRS Quebec City] 3. MSc (Hydrological Modeling) - Modeling predicted thermal regimes downstream during reservoir drawdown. The objective of the project is to predict reservoir temperatures and the water temperature downstream of the dam under various release scenarios to minimize the temperature impacts. Working closely with a PDF mainly responsible for downstream scenarios, the M.Sc. candidate will concentrate on establishing the reservoir temperature conditions. To account for vertical thermal variability in the reservoir, e.g., seasonal stratification, a CEQUEAU thermal model complemented by a 1D vertical water temperature model called MyLAKE(Multi-year Lake Page 1 of 5 simulation model) will be used. Thermal indices will be computed from synthetic temperature time series. These indices are descriptive statistics that quantify spatio-temporal variability in water temperature amplitude, frequency, timing and duration of warm events, and will be compared with habitat maps and biota distribution to examine implications for dam removal and longer term, environmental flow regimes. [Supervisor Dr. Andre St-Hilaire, INRS Quebec City – note that proficiency in French is required] 4. PDF (Civil/Hydrodynamic Modeling) - Sediment resuspension, movement, and fate post-dam removal - The PDF will develop, calibrate and validate a hydrodynamic model that includes the entire study area of the reservoir and river reach. The project will then integrate the bathymetric surveys and reservoir sediment volume, grain size, and spatial distribution analyses into “Delft3d” model that simulates the interaction of water and sediment (both suspended and bed total load) in time and space (http://oss.deltares.nl/web/delft3d). Long- and short-term morphological changes and sediment distributions will be predicted to best understand how disturbed materials will move in the water column and their ultimate fate. This dynamic-bed model will simulate seasonal streamflows to investigate the optimal timetable for the dam removal to mitigate downstream effects of suspended sediment concentration and spatial patterns of sediment deposition.[Supervisor Dr. Katy Haralampides, UNB Fredericton] 5. PhD (Limnology) - Chemical and biotic source materials from the reservoir drawdown. In a dam removal scenario, ~350km3 of water must be displaced downstream. The PhD Candidate will conduct a complete, spatio-temporal analyses of the reservoir’s limnological conditions to understand the physical-biological characteristics of water released in a dam removal scenario. The survey will produce data to build and assess a model of downstream dispersal for various biological components (e.g., nutrients, alga, contaminants, dissolved oxygen) using a DELWAQ model, D-Water Quality and D-Ecology modules. We plan to develop and test a rapid phytoplankton assessment tool using an ‘bbe AlgaeTorch’ (www.bbe-moldaenke.de) as a rapid vertical profiling sampling protocol to increase our data for modeling and also provide guidance data during the drawdown regime when reservoir limnological responses will be intensified by declining water volumes and effects on temperature, concentrations of nutrients, and biota. [Supervisor Dr. Allen Curry, UNB Fredericton] 6. M.Sc. (Aquatic ecology) -River metabolism. Led by the M.Sc. Candidate, the project will first determine the metabolism of the planktonic and benthic communities using the light/dark bottle incubation and benthic chamber techniques. The objective is then to determine an appropriate reaeration coefficient for an open water metabolism method applicable for regulated rivers such as the SJR.[Supervisor Dr. Joseph Culp, UNB Fredericton] 7. PhD (Fish Ecology/Biotelemetry) - Reservoir transit and downstream approaches to a large dam by Atlantic Salmon. Downstream movements of Atlantic salmon present challenges at two spatial scales. The capability of smolts (downstream) and adults (upstream and downstream) to negotiate the ~100km reservoir is not understood. The PhD Candidate will use acoustic tracking with multiple fixed receivers (www.vemco.com) and manual tracking, to track smolts, kelts and upstream migrating adults during a multi-year field campaign. Pathways will be mapped and synthesized with limnological data to best understand reservoir bottlenecks. The finer scale 3D movement by downstream migrants during the approach to the dam will use a 16 antenna, high performance hydro-acoustic array (HTI) at the upstream face of the existing dam to understand mechanisms dictating dam passage. Position will start fall 2014, with field activity planned in spring 2015. [Supervisors Dr. Tommi Linnansaari and Dr. Steve Peake, UNB Fredericton] 8. PhD (Fish Ecology/Biotelemetry) - Restoration potential for reproduction by Striped Bass. Because Striped Bass still migrate and are distributed throughout the SJR up to MD during its spawning period, it is a candidate for population recovery using engineered reproductive habitats downstream of MD, e.g., by manipulating flows. The PhD Candidate will locate the preferred seasonal habitats of striped bass using a combination of radio and acoustic telemetry and will link movement behavior to physical habitat variables (e.g. depth, velocity, substrate, temperature, and flow) and Page 2 of 5 biological understanding (e.g. prey abundance) to generate an understanding of the basic ecology of the species in the river. Verification of habitat use and presence of associated fish species will be carried out by using SeaViewer underwater camera system operated on a georeferenced transect grid. Potential spawning areas will be further refined by capturing fish using traps and electrofishing during the spawning period. Using observations from tracking and river environment maps created in the other projects, we will build a model of potential spawning habitat as a function of discharge using River2D for the current and future river scenarios. In-stream and in-hatchery experiments (Mactaquac Biodiversity Facility, Fisheries and Oceans Canada)